Boost Issue: VagCom Logs

[Aronis]

I found the source of the new rattle and probably the cause of the speed sensor error.

Anyone know what size bolt holds that bracket on?

And now the the bracket is touching the new CV Boot D'ooh.

I pulled the air cleaner off and checked all the hoses I could see. Nothing was obviously off or torn.

I re-seated the MAF wires and at the same time finally figured out the Easy Way to plug them in and re-seat the unit.

I started the car briefly while on the jack so I could turn the wheel to the right to get the photos here. It did not sound that great, even though I cleared the codes yesterday when I got back from my near dead car experience. I can't drive it until I replace that bolt. I don't want to mess around with that hanging and scraping the new boot.

Oh, I unplugged the wear indicator wire so I could clean the bracket off. It was still covered in CV boot grease.

Mike

PS. I did not want to bitch at my mechanic, stuff happens, but a bit disappointed when I see a missing screw or bolt.

[Aronis]

Oh no! Mike, have you opened the box yet? Last time I ordered "OEM" parts from partsgeek, I got flat (non-drilled) one-piece rotors, and it cost me $50 to return them... Hope you're having better luck with them than I did!

O_E

This is what I ordered....

Looks correct, but who knows. If they are wrong I'll let my credit card company deal with them. The value of a platinum card vs fraud claim.

[G2]

Using brake clean or propane can help chase down vaccum leaks. Both by changes in data and how the engine runs. Maybe the MAF's are leaking?

Similar experience on a 2012 A5 2.0T recently. PCV diaphragm failed, still made boost however.

[G2]

Last reply was obviously late-- didn't refresh the page.

BOLT: it's a 6x1.0, maybe 12 or 16mm long. Shouldn't matter if it's too long....can cut it shorter if needed. Torque is typically 10NM/89 in/lbs. keep in mind the "nut" is alluminum.

I always make sure the bracket is tight and/or loctite the bolt.

I've yet to see any shop or tech clean grease from a failed CV boot. It's a mess and takes time; no one want's to pay for. But should be done. Greasy messes on a car like this peeves me, and clean them up. So far 75% of RS6's I've laid a wrench on have needed at least one axle replaced. Whether stock or lowered.

[Aronis]

I did it the "easy" way. I pulled the tire on the other side and removed the bolt. Yes 6 mm. I found what I need at Advanced Auto Parts, and then put both bolts back in. The speed sensor looks fine. I cleaned the rest of the grease anyway .


I pulled the air cleaner/ MAF again since I had a MAF intermittent connection, when I looked at the back I noted the connector was not seated all the way. So I looked at the connector more closely than EVER before And found the culprit. The pink part was broken and a piece was jammed in the connector and keeping it from seating. Now it is seated.




By the way the two conical wire mesh baskets which I have wrestled with TOO many times can be reversed in the housing. Unless some one can give me a reason why it has to be sticking out????

The engine is running rough. I put everything back to gather, now time to drive it and measure and log blocks.

Mike

[Aronis]

Great News....

I took the car out for a test drive and it about back to normal. A little rough when I first started it, but after a short run down the street and back, I went for a longer run with runs to WOT in 1,2 and 3rd. Got a max boost logged at 1480. No lights, no hiccups, NO CODES when I scanned at the end.

It was due to the loose wire (bracket not remounted) and a MAF connector which was not seated all the way (probably has been an issue for several years, who knows when that connector was broken).

I'll do another drive tomorrow and see if it stays 'normal.'

Thank you all for your helpful input and patients with me.

Mike

[DHall1]

Bingo strikes twice in one thread.

I really need a steak dinner one of these times. Lol

Two issues

Rough running can be a vac hose or that maf issue. Inspect that maf connector

Speed sensor is the other issue

Most likely not a boost hose but checj them just the same....one could be partially off.

Boost is a tad low and its lean but fix the two known issues first. For whatever reason your ecu is only requesting .4bar and for the most part u r hitting that level.

[Aronis]

Ok. Come on by and I'll fire up the Weber.

[Aronis]

Bad News..
It's dead again....

It ran great last night, but when I started it this morning was running terribly and I got these new errors.

Does this make sense? Could the O2 sensor been going but not giving an error before?

Mike

Address 01: Engine Labels: 077-907-558-BCY.lbl
Part No: 4D1 907 558 D
Component: 4.2l V8/5VT G 0003
Coding: 0006752
Shop #: WSC 02195 785 00200
VCID: 2F6DD65ABD1EA459C75-5140

2 Faults Found:
16518 - Oxygen (Lambda) Sensor B1 S1
P0134 - 004 - No Activity - Intermittent
16538 - Oxygen (Lambda) Sensor B2 S1
P0154 - 004 - No Activity - Intermittent
Readiness: 0000 1101

[Dmb408]

I vote suction jet pump just because your idle descriptions are what happens when that is failing and it gives "pre" symptoms (like you had) before it really fails (and you have no vac boost).

[Aronis]

Dmb408, "No Vac Boost?"

Found it...LOL...I'll check it out. No I did not...it that GD thing located under the intake manifold? WFT? Why? Why?

arrrrrggggg...

Thanks,

Mike

[Dmb408]

I'm pretty sure our brakes use vacumm boost...to add the power to the brakes... http://en.wikipedia.org/wiki/Automob...y_power#Vacuum

The suction jet pump sits in a nest of vac hoses below the intake manifold. My understanding is the pump routes the on and off boost vacuum pressure in the PCV system but someone smarter than me can jump in and correct me.

[Dmb408]

My understanding is VAG uses the same crappy (prone to fail) suction jet pump on everything since their 1.8t's but i could be overgeneralizing and probably am.

[Aronis]

It's odd that that part would just go all of a sudden without any other error messages like it before.

I suspect a loose O2 sensor connection....I'll go look at the fire wall.

Mike

[Dmb408]

yea it's weird when it fails, i didnt even get cylinder misfire codes, my understanding is that it cracks and gets a leak before failure, or the valve starts to fail over time.

[Aronis]

Off to the mechanic. The Q7 did a great job towing the 4200 pound car and the 1500 pound trailer....LOL....

(I'll keep it a secret that I tore the passenger side bumper cover when taking the dam thing off the trailer...dam....don't tell anyone.) Oh dam you saw that! Oh well.

[Aronis]

Culprit found.....I folded over a seal on the intake below the air cleaner/MAF assembly. D'ooh

[MaxRS6]

Woo hoo! Congrats on a relatively easy fix